Yes, it’s very common for officers/employees of the agency which made the regulatory decision to appear as witnesses in the AAT if there is a review of the decision, and as witnesses for the prosecution in a prosecution under the legislation administered by the agency.
These officers/employees can have two related but very different roles.
The first is to be witnesses of fact: What actually happened, when?
The second is to be witnesses of opinion.
Normally evidence of someone’s opinion is
inadmissible. However, an exception is the opinion of an independent expert in the subject matter of something relevant to the review/claim/prosecution.
Would this injury result in a probability of seizures greater than that in the normal population? What are the likely causes of a sudden increase in the EGT of a single cylinder of a normally aspirated IO520?
The expert must express an independent opinion about the technical/specialist subject matter,
not be an advocate for the decision made by the regulator or the guilt of the defendant.
There seems to be a spate of CASA witnesses called to give opinion evidence but are considered by the Court/AAT to be partisan rather than independent.
